134 ERRORS REGARDING THE DURATION OF LIFE. 



ing from the excess of births over deaths, and from immi- 

 gration. In our registration report of 1875 it is said 

 "In these thirty-five years, a period within which an en- 

 tire generation of mankind has passed through its stages 

 of infancy, maturity, and decay, the registration officers 

 of Massachusetts have recorded the facts concerning 

 761,428 deaths within the borders of the State." 



After reading the report I called on the author and put 

 this question to him : "How did you succeed in getting rid 

 of a generation in thirty-five years, when but two per cent 

 a year of deaths have taken place for the last thirty-five 

 years?" His reply was : " According to latest authorities 

 the length of a generation was thirty -four }'ears ; and as the 

 population of 1840 was 737,700 and as 761,428 deaths 

 occurred in the thirty-five years which was 23,728 more 

 than the population of 1840, this would favour the idea of 

 a generation passing away in thirty-four years." Now, if 

 the population of the state had remained stationary for 

 the thirty-five years this calculation would have been cor- 

 rect, but unfortunately for his calculation that was not the 

 case. The population of the state in 1840 was 737,700 ; 

 in 1875 it was 1,651,912, making a gain in thirty-five 

 years of 890,484 which was 152,784 more than the popu- 

 lation of 1840, with all the deaths taken out. He should 

 have found what the average population for the thirty-five 

 years was, which was 1,210,277, and this would give 

 fifty-five years for a generation to pass away. The first 

 attempt to prove by statistics that a generation passes 

 away in thirty-five years was a complete failure. The in- 

 crease of population is greater than the deaths for eleven, 

 thirty-five or one hundred years, taking the population of 

 1875, and is a larger number than the deaths for the pre- 

 vious hundred years. Massachusetts Registration Re- 

 ports demonstrate that the deaths under five years for 

 eleven, thirty-five or one hundred years, do not amount 



